The Brookdale Hospital Medical Center ("Hospital") is a 1,023-bed voluntary hospital in northeastern Brooklyn serving a population of approximately 750,000 people. The Hospital is affiliated with State University of N.Y. Health Science Center in Brooklyn and Downstate Medical Center and is approved for housestaff training by the AMA and the JCAH. There are presently 300 residents and fellows in training. The Hospital has been designated as a Renal Center. The Division of Nephrology & Hypertension ("Division") includes 6 full-time board certified nephrologists and 5 fellows. The members of the Division are also associated in a private practice group ("Group") at the Hospital. The Investigators in this Study (all members of the Division/Group) have had extensive experience dealing with patients with chronic renal failure and have conducted collaborative clinical research studies. They are similar with all the techniques and procedures employed in the MDRD protocol. In addition to patients generated through the Hospital and its clinics, there are 3 large HIP/HMO groups serving 235,000 patients who refer all their nephrological problems to the Division, and have agreed to support this Study. With an average of approximately 285 new patients seen each year (for 1984-86), many of whom are followed long term by the Group, it is estimated that there are presently identified approximately 115 patients eligible for the MDRD Study and that during this year 1987) and the 2 recruitment years of the Study (1988-89) 150 more patients will be added who are eligible. With only 25% of the patients consenting (and successfully completing the baseline period), there will be at least 60 patients eligible to complete the Study. In addition to the large number of patients available, the hospital has committed a 1400 sq. ft. Study Center (with all the necessary furniture and equipment) to accommodate all aspects of the MDRD Study with space for all the personnel. Furthermore, the requisite support has been obtained from Clinical Laboratories, Pharmacy, Nuclear Medicine and the Department of Medicine and the Hospital is agreed to cooperate in every way possible with the project (in addition to providing the renovated space), including support from the Personnel, Purchasing and Fiscal Departments. The personnel requested conform to the RFA Guidelines and the investigators are committed to scrupulously carrying out the protocol and cooperation the other Clinical Centers, the NIDDK staff and the Executive Committee.